This invention relates to thermosetting monomers and polymers having aromatic ether moieties and pendant hydroxyl moieties in the backbone chain, benzocyclobutene moieties at chain ends and to articles prepared therefrom.
Benzocyclobutene compositions are known to be useful in preparing thermoset and thermoplastic polymeric compositions. Such polymeric compositions are well-known as "self-curing" materials since they do not require an added curing agent, catalyst or comonomer to obtain effective crosslinking. Benzocyclobutenes cure upon application of heat. Such cured thermoset polymeric compositions have properties of rigidity, strength, and chemical resistance and are useful in many engineering applications such as coatings, structural laminates, adhesives, films, and composites. Desirable physical properties include enhanced chemical resistance, high tensile strength, high temperature resistance, electroinsulative or electroconductive properties, and oxidative stability.
A series of patents issued to Wang, illustrated by U.S. Pat. Nos. 4,954,583; 4,954,584; and 5,068,396, describes the preparation and curing of benzocyclobutene compositions that are prepared by contacting 1-benzocyclobutenecarboxylic acid with glycidyl ethers of bisphenols such as 2,2-bis(4-hydroxyphenyl)propane, wherein the linking group between the 1-benzocyclobutene carboxylate and the dioxydiphenyleneisopropylidene moiety is a 2-hydroxy-1,3-propylidene unit. The carboxy group connects the benzocyclobutene moiety to the remainder of the molecule by attachment to a carbon of the four-membered ring. Upon curing, such thermosetting resins have glass transition temperatures that are limited to 120.degree. to 135.degree. C.
It would be desirable to provide new thermosetting monomers having glass transition temperatures that are greater than 135.degree. C. after curing.